Technologies have arisen that allow near field coupling (such as wireless power transfers (WPT) and near field communications (NFC)) between wireless portable devices in close proximity to each other and more particularly, thin portable electronic devices. Near field coupling functions use radio frequency (RF) antennas in each of the devices to transmit and receive electromagnetic signals. Because of user desires, and/or for esthetic reasons, many of these portable wireless devices are small, and are becoming smaller as markets evolve, and tend to have exaggerated aspect ratios when viewed from the side. As a result, many thin portable devices incorporate flat antennas, which use coils of conductive material as their radiating antennas for use in near field coupling functions.
Meanwhile, (capacitive) proximity sensors may be used in tablets (portable device) with embedded wireless wide-area network (WWAN), such as a third generation or a fourth generation (3G/4G) digital radio, in order to pass Federal Communications Commission (FCC) regulations such as, specific absorption rate (SAR). For example, the proximity sensors may detect human body within proximity, and may use a sensor electrode of relatively large size to implement proximity detection. Both the NFC and the proximity sensor devices may require significant space in a portable device and neither may be covered by metallic chassis/shielding. In other words, the NFC and the proximity sensor devices may be competing for a very limited space for antennas on the wireless device (e.g., tablets). The limited space even becomes more challenging as the portable device gets thinner and adopts a full metallic chassis. To this end, performances of the NFC and/or the proximity sensor may be compromised when their respective sizes get compacted in order to fit within a thin portable device. Accordingly, a solution may be implemented to provide efficiency on performances of the proximity sensor and the NFC devices in the thin portable device.
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